In the related art, after both two mobile terminals are located in a Network Address Translation (NAT) network, and the NAT network comprises an address (such as an Internet Protocol (IP) address or a port)-related mapping, then the two mobile terminals cannot directly communicate with each other. At this time, a relay server is needed to act as an intermediate node; an Internet Engineering Task Force (IETF) Request for Comments (RFC) 5766 defines a Traversal Using Relays around NAT (TURN) protocol to control interactive operation and data exchange between each one of the two mobile terminals and the relay server. All messages and data are transmitted via the relay server, so the relay server is only used if the direct communication cannot be implemented, and it is only available to an authorized user.
FIG. 1 is a schematic diagram showing a network mode of a relay server according to the related art. As shown in FIG. 1, because of resource limitation of an IPV4 address, an NAT equipment is usually set between a user terminal equipment and the relay server, and limitations of IP addresses and ports usually exist in the NAT equipment, thereby the user terminal equipments cannot directly communicate with each other. In the related art, a service server and the relay server are usually located in a public network, and each of them respectively has its own user information database; if the user terminal equipment wants to use the service server and the relay server, the user terminal equipment must respectively pass authentication performed by the service server and authentication performed by the relay server.
The relay server authenticates the identification of the mobile terminal in an assignment request; if the identification of the mobile terminal is valid, then the mobile terminal is permitted to use the relay server, which is a long-term credential mechanism stated in a Session Traversal Utilities for NAT (STUN) specification, and it requires the mobile terminal to obtain a user name and password from the relay server in advance. For preventing offline dictionary attacks, the required length of the password is usually 128 bits, and they are some randomized characters. Obviously, it will be very difficult for a user to input the password manually. So it is the problem needed to be solved that which way adopted to set the password for the user to access the relay server can be convenient for the user to input while effectively preventing offline dictionary attacks.
Aiming at the problem in the related art that when the user equipment needs to transmit and/or receive data through the relay server, the service server and the relay server are required to authenticate the user equipment respectively, which increases the operation complexity of the user, no effective solution has been presented currently.